The FT600 is a high speed USB 3.0 FIFO bridge with up to 5Gbps of bandwidth. It comes with the option of 16 and 32 bits wide parallel FIFO interface. FT600Q is a 56-pin QFN package with the 16-bit option and FT601Q is a 76-pin QFN package with the 32-bit wide FIFO bus interface. Both of these chips support up to 8 endpoints other than the management endpoints.
They offer flexibility as far as the communication packages are concerned. The 245 FIFO mode offers a simple typical protocol for any design. The multi-channel mode is a more sophisticated solution which supports up to 4 logical FIFO channels to optimize data structures and therefore increase data flow. The FIFO is provided with a 16kByte configurable buffer.
Find more info about this chip here
Here is the FTDI chip brochure
A preliminary datasheet of the FT600/601 series under this link